roll_dice
Simulate dice rolls using standard notation to generate random numbers for games, probability calculations, or decision-making.
Instructions
Roll the dice with the given notation
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| notation | Yes | ||
| num_rolls | No |
Output Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Implementation Reference
- server.py:21-25 (handler)The main handler function for the 'roll_dice' MCP tool, decorated with @mcp.tool() which registers it with the FastMCP server. It instantiates DiceRoller and returns its string representation containing the roll results.
@mcp.tool() def roll_dice(notation: str, num_rolls: int = 1) -> str: """Roll the dice with the given notation""" roller = DiceRoller(notation, num_rolls) return str(roller) - dice_roller.py:10-23 (helper)Core implementation of dice rolling logic within DiceRoller class: parses dice notation (e.g., '2d6k1'), generates random rolls, sorts descending, keeps top N rolls, and returns all rolls and kept rolls.
def roll_dice(self): match = self.dice_pattern.match(self.notation) if not match: raise ValueError("Invalid dice notation") num_dice = int(match.group(1)) dice_sides = int(match.group(2)) keep = int(match.group(4)) if match.group(4) else num_dice rolls = [random.randint(1, dice_sides) for _ in range(num_dice)] rolls.sort(reverse=True) kept_rolls = rolls[:keep] return rolls, kept_rolls - dice_roller.py:37-47 (helper)__str__ method of DiceRoller that formats the output string returned by the tool handler. Handles single or multiple rolls, calling roll_dice() or roll_multiple().
def __str__(self): if self.num_rolls == 1: rolls, kept_rolls = self.roll_dice() return f"ROLLS: {', '.join(map(str, rolls))} -> RETURNS: {sum(kept_rolls)}" else: results = self.roll_multiple() result_strs = [] for i, result in enumerate(results, 1): result_strs.append(f"Roll {i}: ROLLS: {', '.join(map(str, result['rolls']))} -> RETURNS: {result['total']}") return "\n".join(result_strs) - dice_roller.py:4-9 (helper)DiceRoller class initialization, storing notation and num_rolls, compiling regex for parsing dice notation supporting 'NdSk' format.
class DiceRoller: def __init__(self, notation, num_rolls=1): self.notation = notation self.num_rolls = num_rolls self.dice_pattern = re.compile(r"(\d+)d(\d+)(k(\d+))?")